This guys got class! When so many others are stumbling over themselves to get a guest spot on the Big Bang Theory, William Shatner decided to give it a miss. Not because he doesn't make cameos but because he didn't like the material.
He told Digital Spy, he wasn’t happy with how it was written initially. Shatner explained what happened the last time there were discussions on the matter:
"I’ve had several conversations with the creators, and what they wanted me to do, didn’t seem to be exactly right, so I said ‘find something that’s better’. They may have taken umbrage at that, I’m not sure. They wanted me to play myself a little obliquely, and they said it would work out, but I needed more assurance on that."
As someone who thinks the writers get away with far too much laziness these days, I have to say I deeply admire Shatner for this and for reminding us its about quality not cash! It's the very reason we loved Big Bang in the early days.